The Barrow-downs or Tyrn Gorthad were a series of low hills east of the Shire, behind the Old Forest, and southwest of the village of Bree.[1] Many of the hills were crowned with megaliths and barrows, hence their name.

During the Second Age they were fairly numerous, and when they met with the Númenóreans the Barrow-downs were the first places where the Dúnedain émigrés from Númenor settled.[3] The Downs were revered because of the Great Barrows. When Elendil returned to Middle-earth, the Barrow-downs were incorporated into the kingdom of Arnor.

After the split of Arnor in T.A.861 the Barrow-downs became the capital of Cardolan. After Rhudaur fell to Angmar in 1409, the Dúnedain of Cardolan entrenched themselves here, but eventually the realm fell. Around T.A.1636[4] the Witch-king sent the Barrow-wights that haunted the hills,[5] preventing any resettlement; after Arthedain once again claimed the kingship over all of Arnor the Dúnedain tried to recolonize Cardolan, but this failed because of the Barrow-wights.

A "barrow" (or "berrow"; from English beorg, berg, 'hill, mound') not to be confused with the wheeled vehicle, is a tumulus or other prehistoric grave-mound.[11]

The name therefore would represent an earlier Old English form Beorga Dune "downs of barrows".[12]

Tyrn Gorthad was the Sindarin name of the Barrow-downs. Tyrn Gorthad is a compound of torn ("down") and gorthad ("of buried").[13] In one manuscript, the name Tyrn Goerthaid was used by Tolkien.[14]Goerthaid seems to be the plural of gorthad with lenited vowels.

The Barrow-downs are a divided into North and South Barrows, depicted as a series of mounds crowned with megaliths. The region is inhabited by wights, recently stirred by the passage of the Nazgûl. The largest and oldest barrow is called Othrongroth.

After Halbarad sends Eradan, Andriel and Farin to warn Aragorn in Bree, the three heroes travel through the Barrow-downs as a shortcut.[15] On their way, they have to save two Dúnedain Rangers named Luin and Kilaran. Throughout the whole level fog hangs above the ground.[16] Upon reaching Rivendell, the three heroes can talk to Frodo about their escapades in the Barrow-downs. Even though Frodo and the Hobbits were never shown to venture into the Barrow-downs in the movies, he will mention his own encounters there. However, he refuses to go into detail about what happened there.